Domestic energy needs currently outpace readily accessible energy resources, which has forced an increasing dependence on foreign petroleum fuels, such as oil and gas. At the same time, existing energy resources are significantly underutilized, in part due to inefficient oil and gas procurement methods.
Petroleum fuels, such as oil and gas, are typically procured from subsurface reservoirs via a wellbore that is drilled by a rig. In offshore oil and gas exploration endeavors, the subsurface reservoirs are beneath the ocean floor. To access the petroleum fuels, the rig drills into the ocean floor down to approximately one to two miles beneath the ocean floor. Various subsea pipelines and structures are utilized to transport the petroleum fuels from this depth beneath the ocean floor to above the surface of the ocean and particularly to an oil platform located on the surface of the ocean. These subsea pipelines and other structures may be made of a metallic material or a combination of metallic materials. The petroleum fuels, such as the oil, originating at a depth from about one to two miles beneath the ocean floor, are very hot (e.g. around 130° C.). In contrast, at this depth, the seawater is very cold (e.g. around 4° C.). This vast difference in temperature requires that the various subsea pipelines and structures be insulated to maintain the relatively high temperature of the petroleum fuels such that the fuels, such as oil and gas, can easily flow through the subsea pipelines and other subsea structures. Generally, if the fuel, such as oil, becomes too cold due to the temperature of the seawater, it will become too viscous to flow through the pipelines and other structures and will not be able to reach the ocean surface and/or oil platform. Even in instances where the fuel may be able to flow, the fuel may flow too slowly to reach the ocean surface and/or the oil platform in an efficient amount of time for the desired operating conditions. Alternatively and/or additionally, the fuel may form waxes that detrimentally act to clog the pipelines and structures. Yet further, due to the cold temperature of the seawater, the fuel may form hydrates that detrimentally change the nature of the fuel and may also act to clog the pipelines and structures.
In other examples, pipelines may be as long as 50 miles and may be both above water and below water. While traveling over such distances, the fuel is exposed to many temperature changes. To complicate these instances, the fuel must also travel, in the pipelines, 50 miles through these temperature changes and from one to two miles beneath the ocean floor to the oil platform above the ocean surface, without losing its integrity. For example, the fuel may need to have a low viscosity to remain flowable during these distances and may need to be adequately uniform, e.g., without detrimental hydrates and waxes.
In view of these types of issues, subsea structures are typically constructed by coating a central tube or passageway with insulation. However, during construction, the ends of the structures typically are non-insulated to allow for welding or other connections to be made to extend the length of the structures. For that reason, the subsea structures must be patched after welding with a polymer to ensure continuity of insulation and overall integrity. However, in many instances, the adhesion (or peel) strength of the applied patch to the substrate is poor, as is the hydrolysis resistance of the resultant patch. Accordingly, there remains an opportunity for improvement.